README: Remove CONFIG_SPI_FLASH_MTD help text

Since the help text is added in drivers/mtd/spi/Kconfig

Signed-off-by: Jagan Teki <jteki@openedev.com>

README

@@ -3090,15 +3090,6 @@ CBFS (Coreboot Filesystem) support
 		memories can be connected with a given cs line.
 		Currently Xilinx Zynq qspi supports these type of connections.
 
-		CONFIG_SPI_FLASH_MTD		spi-flash MTD layer
-
-		Define this option to use mtd support for spi flash layer, this
-		adapter is for translating mtd_read/mtd_write commands into
-		spi_flash_read/spi_flash_write commands. It is not intended to
-		use it within sf_cmd or the SPI flash subsystem. Such an adapter
-		is needed for subsystems like UBI which can only operate on top
-		of the MTD layer.
-
 		CONFIG_SPI_FLASH_DATAFLASH	SPI based Dataflash
 
 		Define this option to access AT45xxx Dataflash chips support